The invention is based on a grinding machine tool receptacle.
From European Patent Disclosure EP 0 904 896 A2, a grinding machine tool receptacle for a hand-held angle grinding machine is also known. The angle grinding machine has a drive shaft that has a thread on the side toward the tool.
The grinding machine tool receptacle also has a slaving means and a lock nut. For mounting a grinding wheel, the slaving means is slipped with a mounting opening onto a collar of the drive shaft and braced against a bearing face of the drive shaft by nonpositive engagement via the lock nut. The slaving means has a collar, extending axially on the side toward the tool, that on two radially opposed sides on its outer circumference has recesses that extend axially as far as a bottom of the collar. From each of the recesses, a respective groove extends on the outer circumference of the collar, counter to the driving direction of the drive shaft. The grooves are closed counter to the driving direction of the drive shaft and taper axially, beginning at the recesses, counter to the drive direction of the drive shaft.
The grinding wheel has a hub with a mounting opening, in which two opposed tongues are disposed, pointing radially inward. The tongues can be introduced axially into the recesses and then in the circumferential direction, counter to the driving direction, into the grooves. The grinding wheel is fixed by positive engagement in the grooves in the axial direction via the tongues and by nonpositive engagement by means of the tapering contour of the grooves. During operation, the nonpositive engagement increases as a consequence of reaction forces exerted on the grinding wheel, which act counter to the driving direction.
To prevent the grinding wheel from running off center when the drive shaft is braked by the slaving means, a stopper, which is movably supported in the axial direction in an opening, is disposed in the region of a recess on the circumference of the collar. In a working position where the grinding wheel points downward, the stopper is deflected axially by gravity in the direction of the grinding wheel and closes the groove in the direction of the recess and blocks a motion of the tongue, located in the groove, in the driving direction of the drive shaft.
The invention is based on a grinding machine tool receptacle, in particular for a hand-held angle grinding machine, having a slaving device, by way of which an insert tool can be operatively connected to a drive shaft.
It is proposed that the insert tool is operatively connectable to the slaving device via at least one detent element, supported movably counter to a spring element, which detent element snaps into place in an operating position of the insert tool and fixes the insert tool by positive engagement. By means of the positive engagement, high security can be attained, and a simple, economical, tool-less fast-clamping system can be created. Unintended running off center of the insert tool can be reliably avoided, even in braked drive shafts in which major braking moments can occur.
By means of the movably supported detent element, major deflection of the detent element in the assembly of the insert tool can be made possible, and as a result on the one hand a large overlap between two corresponding detent elements and an especially secure positive engagement can be attained, and on the other, a clearly audible snap-in noise can be achieved, which advantageously tells the user that the snap-in operation has been completed as desired.
The detent element can fix the insert tool by positive engagement either directly or indirectly via an additional component, for instance via a detent lever or tappet and the like that is coupled with the detent element and is supported rotatably and/or axially displaceably. The detent element can fix the insert tool by positive engagement directly and/or indirectly in various directions, such as the radial direction, axial direction, and/or especially advantageously the circumferential direction. It is also possible that as a result of the positive-engagement fixation of the insert tool with the detent element in a first direction, such as the radial direction, the insert tool is fixed by positive engagement in a second direction, such as the circumferential direction, by means of a component that is separate from the detent element.
The movably supported detent element can be embodied in various forms that appear useful to one skilled in the art, for instance as an opening, protrusion, peg, bolt and the like, and can be disposed on the insert tool and/or on the slaving device. The detent element itself can be supported movably in a component in a bearing location, for instance in a flange of the slaving device or in a tool hub of the insert tool. However, the detent element can advantageously also be solidly connected by nonpositive, positive and/or material engagement to a component supported movably in a bearing location, or can be embodied integrally with such a component, for instance with a component supported on the drive shaft or with a tool hub of the insert tool.
Also by means of the positive engagement, an advantageous encoding can be achieved, so that only the intended insert tools can be secured in the grinding machine the tool receptacle. The slaving device can be embodied at least in part as a detachable adapter part, or it can be connected nondetachably to the drive shaft by nonpositive, positive and/or material engagement.
With the grinding machine tool receptacle, various insert tools that appear useful to one skilled in the art can be secured, such as insert tools for severing, grinding, rough-machining, brushing and so forth. A tool receptacle of the invention can also be used to secure a grinding plate of eccentric grinding machines.
The detent element can be embodied movably in various directions counter to a spring element, for instance in the circumferential direction or especially advantageously in the axial direction, making a structurally simple embodiment attainable.
In a further feature of the invention, it is proposed that a drive moment can be transmitted via a positive-engagement connection between the insert tool and the slaving device. A major drive moment can be securely transmitted, and moreover, it is possible to prevent a drive moment from acting on a nonpositive connection.
If the detent element can be released from its detent position by an unlocking button and in particular is movable counter to the spring element, then an independent release of the detent connection which could for instance be caused by a braking moment can be reliably prevented, thus enhancing safety. Operation of the insert tool in two circumferential directions can be made possible in principle, making it more convenient to install and remove the insert tool.
It also proposed that the insert tool is connectable to the slaving device via a tongue-and-groove connection, which is secured by positive engagement via at least one detent element in an operating position of the insert tool. With a tongue-and-groove connection an especially space-saving, lightweight construction can be attained in which individual components are used for multiple functions, for instance the detent element and/or spring elements engaging grooves for radial centering, fixation in the axial direction, and/or fixation in the circumferential direction.
However, if the insert tool is connected to the slaving device in the circumferential direction via at least a first element and in the axial direction via at least a second element, then simple, economical tool hubs can be achieved which can advantageously be embodied in plane form. The tool hubs can be prevented from catching on each other in production and storage, and good manipulation of the insert tool with its tool hubs can be made possible. In addition, the components can advantageously be designed for their function, that is, either for the fixation in the circumferential direction or the fixation in the axial direction. The elements can be formed by one component or advantageously by separate components. The tool hubs can simply and advantageously be embodied with a closed centering bore, and low-vibration action of the insert tool can be made possible. In addition, given a suitable choice of the diameter of the centering bore, it is possible for the insert tools intended for the grinding machine tool receptacle of the invention to be secured to conventional grinding machines via fastening elements that have been known previously, specifically via fastening elements in which the insert tool can be fixed positively in the axial direction and nonpositively in the circumferential direction by an adjusting nut and a tensioning flange on the drive shaft against a bearing face.
In a further feature, it is proposed that at least one detent element, extending in the axial direction, snaps into a recess, corresponding to the detent element, of a tool hub of the insert tool in an operating position of the insert tool and fixes the insert tool in the circumferential direction by positive engagement. With a structurally simple embodiment, an advantageous positive engagement in one circumferential direction and preferably in both circumferential directions can be attained. The detent element extending in the axial direction can be formed by a separate bolt or a formed-on peg produced for instance by a deep-drawing operation.
Advantageously, at least one detent element extending in the axial direction is secured in a component supported displaceably on the drive shaft counter to the spring element. One and especially advantageously a plurality of detent elements via a large bearing area on the drive shaft. Tilting of the detent elements and relative motion of the detent elements can be reliably avoided, and with a spring element that can advantageously be disposed centrally and rotationally symmetrically, a desired spring force for a detent operation can be achieved. However, it is also possible for one or more detent elements, each at bearing points, to be embodied as displaceable counter to a respective spring element or counter to one common spring element.
It is also proposed that the slaving device has at least one fastening element, extending in the axial direction, which element can be passed through at least one region of an elongated slot of a tool hub of the insert tool and in the elongated slot is displaceable in a narrowed region of the elongated slot, and by way of which element the insert tool is axially fixable in the elongated slot via a contact face disposed on the fastening element. The tool hub can advantageously be embodied economically and essentially plane and can be used as a spring element, for instance by providing that the tool hub is elastically deformed upon displacement of the component in the elongated slot. The tool hub can also be used to deflect a component counter to a spring element in the axial direction. This economizes on additional components, assembly effort, and expenses.
To make a long spring travel of the tool hub possible, advantageously a component forming a bearing face for the insert tool, in the fastened state of the insert tool, has a recess in the region of the elongated slot, into which recess part of the tool hub is pressed elastically, in an operating position of the insert tool.
If the fastening element extending in the axial direction is supported elastically displaceably in the axial direction counter to a spring element, for axially the insert tool, then on the one hand an advantageously long spring travel can be attained independently of the tool hub, and on the other, the component and the spring element can be designed in a targeted way for their separate functions. However, the fastening element can also be embodied integrally with a spring element, at least in part. If for axial fixation a plurality of components extending in the axial direction are provided, then they can each be loaded via a respective spring element or advantageously all via one common spring element, making it possible to economize on additional components, assembly effort, weight, and expense.
To attain advantageous centering and low-vibration action of the insert tool, a collar by way of which the insert tool can be radially centered is preferably formed onto a component of the slaving device that forms a bearing face for the insert tool. A self-contained centering face can simply be formed. Forces on the insert tool in the radial direction can advantageously be absorbed by positive engagement, such as forces in the radial direction upon cutting of some object. Forces in the radial direction can be prevented from acting on components that are axially displaceable, thus preventing consequent damage or wear to these components. Furthermore, radial play of the insert tool is reliably avoided, making better concentricity attainable. In principle, instead of a collar, an indentation is also conceivable, which the tool hub engages with a protrusion in the fastened state.
If at least one detent element is formed integrally on a disklike component and/or if at least two elements for fixation of the insert tool in the axial direction are integrally formed onto a disklike component, then additional components and installation effort and expense can be saved. Furthermore, press-fitted connections between individual components with the attendant weak points can be avoided.